北城以北丢失的爱念越难以南不归的思念
[bĕi chéng yĭ bĕi diū shī de ài niàn yuè nán yĭ nán bù guī de sī niàn]
Implies the idea of 'lost love in North of the Northern City' becoming more challenging to abandon over time, thus turning into a lingering nostalgia. It suggests a deep longing for a past romance located geographically north, and how this longing grows stronger and harder to suppress with time.